Cleansing Bars

ABSTRACT

Described herein, are personal care compositions comprising a cleanser base comprising at least one cleanser selected from a soap and a surfactant; and an effective amount of an antibacterial system comprising a combination of phenoxyethanol and piroctone, or a salt thereof. Methods of making and using these compositions are also described.

BACKGROUND

Bar soaps are popular products for body cleansing. Some bar soapscontain one or more compounds that possess antibacterial properties toprovide effective cleansing. One such compound which has been usedextensively in bar soap formulations is triclocarban, (i.e.,3-(4-chlorophenyl)-1-(3,4-dichlorophenyl)urea).

However, there is a continuing need for novel and effectiveantibacterial systems for personal cleansing applications, such as barsoaps. The present invention is directed to this, as well as other,important ends.

BRIEF SUMMARY

It has surprisingly been found that a combination of phenoxyethanol andpiroctone, or a salt thereof such as piroctone olamine, can provideexcellent antibacterial efficacy in a personal care cleansingcomposition, and in particular, bar soaps. Thus, in some embodiments,the present disclosure provides a cleansing composition comprising: atleast one cleanser chosen from soaps and surfactants; and anantibacterial system; wherein the antibacterial system comprises aneffective amount of a combination of phenoxyethanol and piroctone, or asalt thereof. In some embodiments, the cleansing composition is a barsoap or cleansing bar. In some embodiments, the piroctone or a saltthereof is, or includes, piroctone olamine. In some embodiments, thecleansing composition further includes petrolatum (also known aspetroleum jelly, soft paraffin or multi-hydrocarbon, CAS number8009-03-8).

In further embodiments, the present disclosure provides methods forpreparing a bar soap cleansing composition, said bar soap cleansingcomposition comprising phenoxyethanol and piroctone, or a salt thereof,wherein the method comprises the steps of providing a mixture orsolution comprising piroctone, or a salt thereof, in a solvent; andincorporating the mixture or solution into a bar soap formulation. Insome embodiments, the solvent can be the phenoxyethanol; or propyleneglycol; or mixtures of both.

In further embodiments, the present disclosure provides methods forremoving bacteria from skin; and methods for inhibiting bacterial growthon skin; comprising washing skin with a cleansing composition asdisclosed herein.

DETAILED DESCRIPTION

Unless otherwise specified, all percentages and amounts expressed hereinand elsewhere in the specification should be understood to refer topercentages by weight. As used throughout, ranges are used as shorthandfor describing each and every value that is within the range. Any valuewithin the range can be selected as the terminus of the range.

As used herein, the term “cleansing bar” or “bar soap” includes, but isnot limited to, bars for cleansing and personal hygienic use comprisinga cleanser chosen from soap and surfactant. The cleansing bar may be asoap bar (soap is the cleanser), syndet (non-soap surfactant is thecleanser), or combar (a mixture of soap and surfactant).

The present disclosure provides cleansing compositions, and inparticular cleansing bars, containing an antibacterial system thatincludes phenoxyethanol and piroctone, or a salt thereof, which ispreferably piroctone olamine.

In one exemplary embodiment, the present disclosure thus provides acleansing composition (Composition 1) comprising:

-   -   at least one cleanser chosen from soaps and surfactants; and    -   an antibacterial system;    -   wherein the antibacterial system comprises an effective amount        of a combination of phenoxyethanol and piroctone, or a salt        thereof; for example any of the following compositions:

-   1.1 Composition 1, wherein the composition is a cleansing bar;

-   1.2 Composition 1 or 2, wherein the piroctone or a salt thereof    comprises piroctone olamine;

-   1.3 Any preceding Composition 1 et seq., wherein the antibacterial    system comprises an effective amount of a combination of    phenoxyethanol and piroctone olamine;

-   1.4 Any preceding Composition 1 et seq., wherein the phenoxyethanol    is present in an amount of from 0.01% to 2% by weight; 0.1% to 1.25%    by weight; 0.5% to 1% by weight; 0.65% to 0.85% by weight; or about    0.75% by weight of the cleansing composition; and the piroctone, or    salt thereof, is present in an amount of from 0.01% to 1.5% by    weight; from 0.01% to 1% by weight; from 0.01% to 0.5% by weight;    from 0.05% to 0.3% by weight; from 0.05% to 0.15% by weight; or    about 0.1% by weight, or about 0.3% by weight of the cleansing    composition;

-   1.5 Any preceding Composition 1 et seq., wherein the phenoxyethanol    is present in an amount of from 0.01% to 2% by weight of the    cleansing composition; and the piroctone, or salt thereof, is    present in an amount of from 0.01% to 1.5% by weight of the    cleansing composition;

-   1.6 Any preceding Composition 1 et seq., wherein the phenoxyethanol    is present in an amount of from 0.1% to 1.25% by weight of the    cleansing composition; and the piroctone, or salt thereof, is    present in an amount of from 0.05% to 0.3% by weight of the    cleansing composition;

-   1.7 Any preceding Composition 1 et seq., wherein the phenoxyethanol    is present in an amount of from 0.5% to 1% by weight of the    cleansing composition; and the piroctone, or salt thereof, is    present in an amount of from 0.05% to 0.15% by weight of the    cleansing composition;

-   1.8 Any preceding Composition 1 et seq., wherein the phenoxyethanol    is present in an amount of from 0.65% to 0.85% by weight of the    cleansing composition; and the piroctone, or salt thereof, is    present in an amount of from 0.05% to 0.15%, or 0.2% to 0.4% by    weight of the cleansing composition;

-   1.9 Any preceding Composition 1 et seq., wherein the phenoxyethanol    is present in an amount of about 0.75% by weight of the cleansing    composition; and the piroctone, or salt thereof, is present in an    amount about 0.3% by weight of the cleansing composition, or about    0.1% by weight of the composition;

-   1.10 Any preceding Composition 1 et seq., wherein the cleansing    composition further comprises petrolatum;

-   1.11 Composition 1.10, wherein the petrolatum is present in an    amount of from 0.1-05% by weight of the cleansing composition;

-   1.12 Composition 1.10, wherein the petrolatum is present in an    amount of from 0.1-2% by weight of the cleansing composition;

-   1.13 Composition 1.10, wherein the petrolatum is present in an    amount of from 0.1-1% by weight of the cleansing composition;

-   1.14 Composition 1.10, wherein the petrolatum is present in an    amount of from 0.3-0.9% by weight of the cleansing composition;

-   1.15 Composition 1.10, wherein the petrolatum is present in an    amount of from 0.3-0.7% by weight of the cleansing composition;

-   1.16 Composition 1.10, wherein the petrolatum is present in an    amount of from 0.3-0.5% by weight of the cleansing composition;

-   1.17 Any preceding Composition 1 et seq., wherein the cleansing    composition comprises one or more soaps and/or surfactants;

-   1.18 Composition 1-1.17, wherein the cleansing composition comprises    one or more surfactants and/or soaps selected from soap chips;    anionic surfactants; nonionic surfactants; cationic surfactants;    amphoteric surfactants; and zwitterionic surfactants.

-   1.19 Any preceding Composition 1 et seq., wherein the cleansing    composition comprises one or more additional components selected    from binders, foam boosters, coloring agents, dyes, pigments,    fragrances, preservatives, fillers, exfoliating/scrubbing particles,    pearlizers, inorganic salts, brighteners, sequestering agents,    opacifiers, free fatty acids, chelating agents (e.g., EDTA),    humectants (e.g., polyols, for example, glycerol), antibacterial    agents, polymers, and any combination thereof;

-   1.20 Any preceding Composition 1 et seq., wherein the at least one    cleanser component comprises from about 20, 30, 40, 50 or 60% by    weight of the composition to about 70, 80, 85, 90 or 95% by weight    of the composition.

The cleansing bar of the present disclosure includes at least onecleanser component. The terms “cleansing agent” and “cleanser”interchangeably refer to soap and/or surfactant. The terms are used torefer to soap alone, surfactant alone, or a combination of soap andsurfactant. The amount of cleansing agent in the cleansing bars of thepresent disclosure can be from 10% to 95% by weight of the composition;for example from about 20, 30, 40, 50 or 60% by weight of thecomposition to about 70, 80, 85, 90 or 95% by weight of the composition.In certain embodiments, the amount of cleansing agent in the cleansingbars of the present disclosure is 50% to 85%; or from 55% to 80%, orfrom 60% to 75%, by weight of the composition.

The term “soap” refers to the salts of fatty acids that are typicallyused to make soap bars. Exemplary soaps can include blends of C₁₆-C₁₈and C₁₂-C₁₄ fatty acids; for example a 65-85 weight % of C₁₆-C₁₈ and15-35 weight % of C₁₂-C₁₄ fatty acids based on the total weight of thesoap. The C₁₆-C₁₈ fatty acids can be obtained from tallow, and theC₁₂-C₁₄ fatty acids can be obtained from lauric, palm kernel, or coconutoils. Suitable ingredients and amounts are: 65 weight % sodium soap, 15weight % water, 7 weight % glycerin, 0.7 weight % sodium chloride, 0weight % sodium hydroxide, and optionally a talc, all together in aglycerin base.

In certain embodiments the cleanser component is or includes ahydrophilic soap chip (e.g., “a base component”). The soap chips usefulherein for the purpose of this disclosure also include but are notlimited to the well known alkali metal salts of aliphatic (alkanoic oralkenoic) acids having about as 8 to 22 carbon atoms alkyl, preferably10 to 20 carbon atoms alkyl chain. These may be described as alkalimetal carboxylates of acrylic hydrocarbons having about 12 to about 22carbon atoms. Any other surfactant can also be present in the soap chipsuch as those mentioned in U.S. Pat. No. 5,139,781 at column 5, line 35to column 11, line 46. In certain embodiments, the amount of soap is 8to 20 weight % of the total composition. In some embodiments, sodiumsoaps are used in the compositions of the present disclosure. In somesuch embodiments, from 1% to 25% of the soap may be ammonium, potassium,magnesium, calcium soaps or a mixture of these soaps.

Soaps having the fatty acid distribution of common vegetable oils may besuitable, e.g., palm kernel oil, palm oil, coconut oil, olive oil orlaurel oil, or the fatty acid distribution of tallow (rendered animalfat). The soap may comprise the fatty acid distribution of anycombination of natural or synthetic fatty acid sources (e.g., anycombination of natural animal or vegetable fats or oils, and/orindividual fatty acids).

Surfactant refers to any anionic, nonionic, cationic, amphoteric, orzwitterionic surfactant. The total amount of surfactant can be anydesired amount. In certain embodiments, the amount of surfactant in thecleansing bar is 1 to 25 weight %, or 1 to 15 weight %. Examples ofanionic surfactant include, but are not limited to, alkyl(C₆-C₂₂)materials such as alkyl sulfates, alkyl sulfonates, alkyl benzenesulfonates, lauryl sulfates, lauryl ether sulfates, alkyl phosphates,alkyl ether sulfates, alkyl alpha olefin sulfonates, alkyl taurates,alkyl isethionates (SCI), alkyl glyceryl ether sulfonates (AGES),sulfosuccinates and the like. These anionic surfactants can bealkoxylated, for example, ethoxylated, although alkoxylation is notrequired. These surfactants are typically highly water soluble as theirsodium, potassium, alkyl and ammonium or alkanol ammonium containingsalt form and can provide high foaming cleansing power. In certainembodiments, examples of anionic surfactants include, but are notlimited to, sodium lauryl ether (laureth) sulfate (average of 2 to 15 EOper mole, such as 2, 3, 4, or 5) sodium cocoyl isethionate, and sodiumcocoyl methyl isethionate. For laundry, examples of anionic surfactantsinclude, but are not limited to, alkyl sulfates, such as sodium laurylsulfate, ammonium alkyl sulfate salts, alkyl ethoxylate sulfates,alkylbenzene sulfonates, such as dodecylbenzene sulfonate, nonionicsurfactants, polyethoxylated alcohols, such as C₁₂-C₁₃ alcohol with anaverage of 6.5 ethoxyl units, polyhydroxy fatty acid amides, such asC₁₂-C₁₃ amide with N-linked methyl or N-linked reduced sugar. Anionicsurfactants can be included in any desired amount. In one embodiment,anionic surfactants are present in the amounts given above forsurfactants.

Examples of zwitterionic/amphoteric surfactants include, but are notlimited to, derivatives of aliphatic secondary and tertiary amines inwhich the aliphatic radical can be straight chain or branched andwherein one of the aliphatic substituents contains about 8 to about 18carbon atoms and one contains an anionic water solubilizing group, e.g.,carboxy, sulfonate, sulfate, phosphate, or phosphonate. Examples of suchcompounds include sodium 3-dodecyaminopropionate, sodium3-dodecylaminopropane sulfonate, N-alkyl taurines and N-higher alkylaspartic acids. Other equivalent amphoteric surfactants may be used.Examples of amphoteric surfactants include, but are not limited to, arange of betaines including, for example, high alkyl betaines, such ascoco dimethyl carboxymethyl betaine, lauryl dimethyl carboxymethylbetaine, lauryl dimethyl alpha-carboxyethyl betaine, cetyl dimethylcarboxymethyl betaine, lauryl bis-(2-hydroxyethyl)carboxy methylbetaine, stearyl bis-(2-hydroxypropyl)carboxymethyl betaine, oleyldimethyl gamma-carboxypropyl betaine, and laurylbis-(2-hydroxypropyl)alpha-carboxyethyl betaine, sulfobetaines such ascoco dimethyl sulfopropyl betaine, stearyl dimethyl sulfopropyl betaine,amido betaines, amidosulfobetaines and the like. Betaines having a longchain alkyl group, particularly coco, may be particularly useful as arethose that include an amido groups such as the cocamidopropyl andcocoamidoethyl betaines. In one embodiment, the zwitterionic surfactantcomprises cocamidopropyl betaine. Zwitterionic/amphoteric surfactantscan be included in any desired amount. In one embodiment,zwitterionic/amphoteric surfactants are present in the amounts givenabove for surfactants.

Examples of nonionic surfactants include, but are not limited to,ethoxylated fatty alcohols (such as the steareth-2 to steareth-100series from Croda Chemicals, Inc. sold under the trademark Brij, such assteareth-2, steareth-4, steareth-10, steareth-20, or steareth-100),polysorbate 20, long chain alkyl glucosides having C.sub.8-C.sub.22alkyl groups; coconut fatty acid monoethanolamides such as cocamide MEA;coconut fatty acid diethanolamides, fatty alcohol ethoxylates(alkylpolyethylene glycols); alkylphenol polyethylene glycols; alkylmercaptan polyethylene glycols; fatty amine ethoxylates(alkylaminopolyethylene glycols); fatty acid ethoxylates(acylpolyethylene glycols): polypropylene glycol ethoxylates (forexample the Pluronic™ block copolymers commercially available fromBASF); fatty acid alkylolamides, (fatty acid amide polyethyleneglycols); N-alkyl-, N-alkoxypolyhydroxy fatty acid amides: sucroseesters; sorbitol esters; polyglycol ethers; and combinations thereof.Nonionic surfactants can be included in any desired amount. In oneembodiment, nonionic surfactants are present in the amounts given abovefor surfactants, for example from 1 to 25 weight %, preferably from 1 to15 weight %.

The cleansing bars can contain water. In certain embodiments, the amountof water is greater than 0 (e.g., from 0.001%) to 20 weight %; to 15weight %, to 10 weight %, from 5 to 20 weight %, or 5 to 15 weight %, or10 to 20 weight %, or 10 to 15 weight %.

Optionally, the cleansing bar can contain foam boosters. Examples offoam boosters include, but are not limited to, certain amphotericsurfactants, cocomonoethanolamide (CMEA), cocoamidopropylamine oxide,cetyl dimethylamine chloride, decylamine oxide, lauryl/myristylamidopropryl amine oxide, lauramine oxide, alkyldimethyl amine n-oxide,and myristamine oxide. in certain embodiments, the amount of foambooster is 2 to 10 weight %.

Optionally, the cleansing bar can contain any additional materials thatare added to personal cleansing or laundry bars. Examples include, butare not limited to, skin conditioning agents, moisturizing agents,binders, foam boosters, coloring agents, fragrance, dyes and pigments,titanium dioxide, chelating agents such as EDTA, sunscreen activeingredients such as butyl methoxy benzoylmethane; antiaging compoundssuch as alpha hydroxy acids, beta hydroxy acids; preservatives such ashydantoins, imidazolines; humectants, polyols such as glycerol,sorbitol, propylene glycol and polyethylene glycols; particulate mattersuch as silica, talc, or calcium carbonate; antioxidants such asbutylated hydroxytoluene (BHT); vitamins such as A, E, K and C;essential oils and extracts thereof such as rosewood and jojoba,particulate matter such as polyethylene beads, jojoba beads, lufa, oroat flour, fillers, exfoliating/scrubbing particles, pearlizers,inorganic salts, brighteners, sequestering agents, opacifiers, andmixtures of any of the foregoing components.

In one embodiment the cleansing bar includes fragrance in an amount of0.001% to 2% by weight of the composition.

In one embodiment the cleansing bar includes pearlizers, such astitanium dioxide, in an amount of 0.01% to 1% by weight of thecomposition.

In one embodiment the cleansing bar includes one or more pigments, suchas chromium oxide green, in an amount of 0.001% to 1% by weight of thecomposition.

In one embodiment, the cleansing bar includes silica, or silicondioxide, incorporated at a level of from about 0.1% to about 15%,preferable from about 1% to about 10%, more preferably from about 3% toabout 7%. Silica is available in a variety of forms, including but notlimited to, crystalline, amorphous, fumed, precipitated, gel, andcolloidal forms.

In one embodiment, the cleansing bar includes free fatty acids toprovide enhanced skin feel benefits, such as softer or smoother feelingskin. Suitable free fatty acids include those derived from tallow,coconut oil, palm oil and palm kernel oil.

In a second exemplary embodiment, the invention includes a method(Method 1) of method of removing bacteria from skin comprising washingthe skin with a cleansing composition according to any Composition 1 etseq.

In a third exemplary embodiment, the invention includes a method (Method2) of method of inhibiting bacterial growth on skin comprising washingthe skin with a cleansing composition according to any Composition 1 etseq.

Piroctone olamine is a solid at standard temperature and pressure (STP),and is typically sold as a powder. The inclusion of PO into a bar soapformula is challenging for at least the reasons that PO is relativelyexpensive; the addition of PO as a powder represents a processchallenge; and when PO is added as a powder, the foam properties of theformula are significantly impacted.

In some embodiments, the invention includes a method (Method 3) ofpreparing a bar soap cleansing composition, the bar soap cleansingcomposition comprising at least one cleanser chosen from soaps andsurfactants; and an antibacterial system; wherein the antibacterialsystem comprises an effective amount of a combination of phenoxyethanoland piroctone, or a salt thereof; the method comprising the steps of:

providing a pre-mixture or pre-solution comprising piroctone, or a saltthereof, in a solvent; and

incorporating the pre-mixture or pre-solution into a bar soapformulation; for example,

-   3.1 Method 3, wherein the solvent comprises phenoxyethanol, or    propylene glycol, or a mixture of phenoxyethanol and propylene    glycol.-   3.2 Method 3, wherein:    -   the solvent comprises propylene glycol;    -   phenoxyethanol is present in an amount of from 0.01% to 2% by        weight of the cleansing composition; and    -   the piroctone, or salt thereof, is present in an amount of from        0.01% to 1.5% by weight of the cleansing composition;-   3.3 Any preceding Method 3 et seq., wherein the cleansing    composition further comprises petrolatum in an amount of from    0.1-0.9% by weight of the cleansing composition;-   3.4 Any of Methods 3.1-3.3, wherein:    -   the solvent comprises the phenoxyethanol or propylene glycol;        and    -   the pre-solution or pre-mixture comprising solvent and        piroctone, or salt thereof, is prepared by combining solvent and        piroctone or salt thereof, and optionally heating to a        temperature up to 120° C.;-   3.5 Method 3.4 wherein the solvent and piroctone or salt thereof,    are heated to a temperature from 60-100° C.; or from 65-80° C.;-   3.6 Any preceding Method 3 et seq., wherein the piroctone, or a salt    thereof comprises piroctone olamine;-   3.7 Any of Methods 3.1-3.5, wherein:    -   the piroctone, or a salt thereof comprises piroctone olamine;    -   the solvent comprises the phenoxyethanol or propylene glycol;        and    -   the pre-mixture or pre-solution comprising solvent and        piroctone, or a salt thereof, comprises from 1-30% by weight        piroctone olamine in said pre-mixture or pre-solution;-   3.8 Any of Methods 3.1-3.7, further comprising providing a second    pre-mixture or pre-solution comprising piroctone, or a salt thereof,    in a second solvent; and incorporating the second pre-mixture or    pre-solution into the bar soap formulation;-   3.9 Method 3.8 wherein the second solvent is selected from a    fragrance, a fragrance dissolved in a solvent, propylene glycol,    phenoxyethanol, ethanol, isopropanol, PEG 400, and glycerol.-   3.10 Method 3, wherein the solvent is, or includes, propylene    glycol;-   3.11 Method 3.10, wherein:    -   phenoxyethanol is present in an amount of from 0.01% to 2% by        weight of the cleansing composition; and    -   the piroctone, or salt thereof, is present in an amount of from        0.01% to 1.5% by weight of the cleansing composition;-   3.12 Method 3.10 or 3.11, wherein the cleansing composition further    comprises petrolatum in an amount of from 0.1-0.9% by weight of the    cleansing composition;-   3.13 Any of Methods 3.10-3.12, wherein the pre-solution or    pre-mixture comprising piroctone, or salt thereof, and propylene    glycol is heated to a temperature from 40-80° C.; or from 50-70° C.;    or about 60° C.;-   3.14 Any of Methods 3.10-3.13, wherein the piroctone, or a salt    thereof comprises piroctone olamine;-   3.15 Any of Methods 3.10-3.14, wherein the pre-mixture or    pre-solution comprising propylene glycol and piroctone olamine, or a    salt thereof, comprises from 1-16% by weight piroctone olamine in    said pre-mixture or pre-solution;-   3.16 Any of Methods 3.10-3.15, further comprising providing a second    pre-mixture or pre-solution comprising piroctone, or a salt thereof,    in a second solvent; and incorporating the second pre-mixture or    pre-solution into the bar soap formulation;-   3.17 Method 3.16, wherein the second solvent is selected from a    fragrance; a fragrance dissolved in a solvent, propylene glycol,    phenoxyethanol, ethanol, isopropanol, PEG 400, glycerol and mixtures    thereof;-   3.18 Any preceding Methods 3 et seq., wherein the at least one    cleanser component comprises from about 30, 40, 50 or 60% by weight    of the composition to about 70, 80, 85, 90 or 95% by weight of the    composition.-   3.19 Any preceding Methods 3 et seq., wherein the piroctone, or a    salt thereof and the solvent are pre-mixed together, e.g., wherein    the piroctone, or a salt thereof is in powder form and combined with    the solvent prior to being combined with any aqueous or hydrophilic    soap components.-   3.20 Any preceding Methods 3 et seq., wherein the heated pre-mixture    is then blended with soap chips, and any other optional components    of the final cleansing bar composition.-   3.21 Any preceding Methods 3 et seq., further comprising the step of    adding additional optional ingredients to the blended pre-mixture    and soap mixture.-   3.22 Any preceding Methods 3 et seq., further comprising the    processing of the final composition to produce cleansing bars.-   3.23 Any preceding Methods 3 et seq., wherein the product cleansing    bars consist essentially of any one of Compositions 1 et seq.-   3.24 A cleansing bar that is prepared according to any preceding    Methods 3 et seq.

The present disclosure further provides the use of an antibacterialsystem comprising phenoxyethanol and piroctone olamine in thepreparation of a cleansing formulation as described herein, for examplewherein the cleansing formulation is a bar soap. The present disclosurefurther provides cleansing compositions prepared by the methodsdescribed herein.

In some embodiments, the piroctone, or salt thereof, is added to thesoap formulation mixture in a pre-mixture or pre-solution. For example,piroctone olamine, which is a solid at standard temperature and pressure(STP), is conveniently dissolved in a suitable solvent, and optionallyheated to form a pre-mixture, or where the heating effects dissolutionof the piroctone olamine, a pre-solution. The resulting pre-mixture orpre-solution can then be combined with soaps, etc., in accordance withany suitable manufacturing protocol for producing cleansing bars as isknown in the art.

In some embodiments, piroctone olamine is dissolved in a suitable amountof phenoxyethanol; i.e., all or part of the phenoxyethanol of thecomposition can be employed as the solvent for the piroctone olamine.Typically, where phenoxyethanol is the solvent for the piroctone olaminepre-mix or pre-solution, the piroctone olamine is present in thepre-mixture or pre-solution in an amount of from 1-30% by weight; forexample 5%, 10%, 15%, 20%, 25% or 30% by weight. In such embodiments,the mixture including the piroctone olamine and phenoxyethanol ispreferably heated to a temperature of from 50-120° C.; for example from60-100° C.; for example from 65-80° C.; preferably to effect partial orcomplete dissolution of the piroctone olamine.

In some further embodiments, the solvent for the piroctone olamine inthe pre-mix or pre-solution includes or consists of propylene glycol.Typically, where propylene glycol is the solvent for the piroctoneolamine pre-mix or pre-solution, the piroctone olamine is present in thepre-mixture or pre-solution in an amount of from 1-16% by weight; forexample 5%, 10%, 15%, or 16% by weight. In such embodiments, the mixtureincluding the piroctone olamine and propylene glycol is preferablyheated to a temperature of from 40-80° C.; for example from 50-70° C.;for example about 60° C.; preferably to effect partial or completedissolution of the piroctone olamine.

In some embodiments, amounts of piroctone, or a salt thereof asdescribed above can be supplemented by addition of a second pre-mixtureor pre-solution comprising piroctone, or a salt thereof, in a secondsolvent, into the bar soap formulation. In some such embodiments, thesecond solvent can be a fragrance; or a fragrance dissolved in a solventas described above. In addition to propylene glycol, phenoxyethanol andfragrance as described above, other solvents suitable for delivery ofpiroctone, or a salt thereof include surfactants, and solventscontaining alcohol functional groups, such as for example ethanol,isopropanol, PEG 400, and glycerol.

The cleansing bars of the present disclosure may be prepared by any ofthe techniques known to those skilled in the art, including both batchprocesses and continuous processes. The first step in the preparation ofthe cleansing bar is typically the preparation of the soap component.Techniques known to those skilled in the art may be used, such as theclassic kettle boiling process or the modern continuous soapmanufacturing process. For example, an appropriate fat, oil, orcarboxylic acid, or mixture thereof, is first combined with a base(e.g., sodium or potassium hydroxide or carbonate) in the presence ofwater to form the soap component. The soap component can then beprocessed and purified to remove excess base and/or glycerol as needed,and formed into chips, pellets, noodles or other solid or semi-solidforms. Optional ingredients such as additional surfactants may also beadded after the removal of excess base but before formation into chips,pellets or noodles. The soap component may then be ground up, suspendedin water and combined with the piroctone, or a salt thereof, andphenoxyethanol; for example by use of a pre-mix or pre-solution asdescribed above.

After addition of the pre-mixture or pre-solution, the mixture isprocessed together with the soap chips and any other desiredingredients, for example by stirring and/or grinding and/or blending,with heating if necessary. After processing, the final composition isthen formed into the finished cleansing bar product.

The cleansing bar may be formed by the extrusion method, and may be ofvarying sizes and shapes such as ovoid or rectangular in shape witheither a flat or curved profile as an overall appearance.

In some embodiments, the cleansing bars of the present disclosure caninclude petrolatum. It has been surprisingly discovered in accordancewith the present disclosure that the inclusion of petrolatum iseffective to improve the antibacterial efficacy of thepiroctone-phenoxyethanol antibacterial system. Thus, in someembodiments, the cleansing compositions of the disclosure includepetrolatum, preferably in an amount of from 0.1-05% by weight, from0.1-2% by weight, or from 0.1-1% by weight, or from 0.3-0.9% by weight,from 0.3-0.7% by weight, or from 0.3-0.5% by weight of the cleansingcomposition; for example in an amount of 0.1%, 0.1%, 0.3%, 0.4%, 0.5%,0.6%, 0.7% or 0.8% by weight of the composition. In some embodiments,the weight ratio of petrolatum to piroctone olamine present in thecleanser composition is from 10:1 to 1:2; for example from 5:1 to 1:2;for example from 4:1 to 1:2; for example from 3:1 to 1:1; for example3:1. 2:1 or 1:1.

Exemplary embodiments of the present disclosure will be illustrated byreference to the following examples, which are included to exemplify,but not to limit, the scope of the present invention.

EXAMPLES Example 1

Table 1 describes an exemplary composition of the present invention.

TABLE 1 Ingredient Wt % Cleanser base  85-98 Phenoxyethanol 0.1-2 Piroctone Olamine 0.01-1.5 Petrolatum  0.1-5% Dye/Fragrance/Otheringredients 0.02-5 

Example 2

Performance properties (use up rate; slough test and cracking) arestudied for soap bars containing either triclocarban (TCC) [ComparativeExample I] or 0.75% phenoxyethanol (PE) and 0.3% piroctone olamine (PO)[Composition I].

Use up (or wear) rates for soap bars is determined by a procedureinvolving weighing the bars before and after multiple cycles thatincluded hand washing employing the bars, and rinsing the bars, followedby drying the bars. A minimum of 2 bars are used, and the results arerecorded as the average of the percent weight loss after a definednumber of cycles.

The slough test determines the bar soap slough (i.e., the soft, mushysoap formed when a bar of soap sits in a puddle of water after aprolonged period of time) at high humidity and room temperature. Thebars are pre-washed, and arranged in a water bath such that they aresitting in a puddle of water at 95° F. After a defined time, the barsare taken out; the slough removed; and the bars are dried. Results arereported as the average of % weight loss; i.e., the average of [(initialbar weight−final bar weight)/(initial bar weight)] for all the barstested.

Cracking is determined by exposing the bars to water and drying them atroom temperature, and visually inspecting them for cracks, and ratingthem on a scale of 0 to 5, where 0 is no cracking and 4-5 indicatessevere cracking.

The results of these evaluations are described in Table 2 (below).

TABLE 2 Property Comparative Example I Composition I Use up rate 8.1%7.5% Slough Test 11.5% 10.8% Cracking 0 0

It can be seen that the exemplary composition of the present invention(Composition I), comprising 0.75% PE and 0.3% PO, has superior use uprate and slough test results relative to the comparative example whichcontains TCC.

Example 3

The antibacterial efficacy of cleansing compositions containing 0.75%PE+various % of PO (0.1%, 0.2% and 0.3%) is evaluated by testing theresidual antibacterial (AB) performance in an in vitro system where thePE and PO are delivered from the bar soap to pig skin.

Ex-vivo Porcine skin is washed with the soap bars using a procedure thatsimulates a consumer hand wash to evaluate residual antibacterialefficacy. Using a gloved hand, porcine skin and bar soaps are moistenedunder running tap water (6 L/min). The bar soap is rubbed against thesubstrate for 15 seconds using light pressure. The substrate is thenlathered for 45 seconds. The substrate is then rinsed for 15 seconds byholding the substrate at a 45 degree angle and allowing the water toimpinge on the top of the substrate and cascade across the entiresurface. Substrate is then lightly patted dry and allowed to air dry for15 minutes before bacteria inoculation. Following appropriate dryingtime a circular area is delineated on the substrate and the center ofthe circular area inoculated with 0.025 ml of bacteria inoculum.Substrate is then incubated for appropriate time at 33° C. At thedesired/appropriate time point the bacteria is harvested using a glasscylinder cup, area=7.1 cm² using Letheen Broth. Harvesting involvespipetting 2 mL of Letheen Broth into a hollow glass cylinder and thenmassaging the skin for 60 seconds with a sterile glass rod andtransferring the fluid to a test tube. The samples are then seriallydiluted 10-fold in Letheen Broth and plated on Microbial Content Agar(MCA), 10³-10⁴ dilutions. The MCA plates are incubated at 33° C. for aminimum of 24 hours. A count for a colony forming unit (CFU) is givenfor measurements in the range of 30-300. If no counts are observed,those plates with the CFUs closest to the range are used. The mean Log₁₀CFU/cm² is calculated, as is the Log reduction of the product calculatedby subtracting the water control and/or placebo—the test sample (Logreduction=Log of Input of Control CFU−Log of Sample CFU). The resultsare shown in Table 3 (below).

TABLE 3 0.1% TCC 0.75% PE + 0.1% PO 0.75% PE + 0.2% PO 0.75% PE + 0.3%PO Mean Log (CFU/7.1 1.83 0.21 0.96 1.78 cm²) Reduction vs Placebo (S.Aureus) Mean Log (CFU/7.1 2.81 1.00 0.87 1.40 cm²) Reduction vs Placebo(E. coli)

The results described in Table 3 (above) show the residual antibacterialperformance of the PE/PO antibacterial system delivered by the barsoaps. These results show that at a PE level of 0.75%, increasing POlevel enhances the Log reduction of the formula.

Example 4

Experiments are conducted to examine the antibacterial efficacy of 0.75%phenoxyethanol/0.3% piroctone olamine plus petrolatum at variousconcentrations (0.3%-0.9%) delivered from a bar soap against E. coli,using the micro test described above. The results are shown in Table 4(below).

TABLE 4 0.75% PE + 0.3% 0.75% PE + 0.3% 0.75% PE + 0.3% 0.75% PE + 0.3%PO + 0.3% PO + 0.5% PO + 0.7% PO + 0.9% 0.75% PE + 0.3% PO PetrolatumPetrolatum Petrolatum Petrolatum Mean Log 1.44 2.64 2.70 1.79 1.12(CFU/ml) Reduction vs Initial Population

The results described in Table 4 (above) show that the addition ofpetrolatum to the PE/PO mixture improved antibacterial performance byone log unit. These results also show that a range of petrolatum loadinglevels enhance the antibacterial performance of compositions comprisinga combination of PE and PO.

Example 5

Experiments are conducted to quantify the deposition of piroctoneolamine in an in vitro skin model. VITRO-SKIN® is removed from itsprotective packaging using gloves, and is cut into 5 cm×5 cm (2″×2″)squares using a paper cutter. Each piece is placed on a shelf/trayinside a humidity chamber, taking care to not overlap the VITRO-SKIN®pieces. The pieces are then incubated in the closed, controlled-humiditychamber for 16 to 24 hours prior to product application/depositionstudies.

A 2 liter beaker of deionized water is pre-heated to 40° C.±2° C. Athermometer is inserted to maintain/monitor at 40° C.±2° C. for theduration of the experiment. The running of tap water is started in asink at 35° C.±2° C., using a faucet thermometer to maintain 35° C.±2°C. for the duration of the experiment. One 2″×2″ piece of pre-hydratedvitro skin from the controlled-humidity chamber is dipped for 5-10seconds, using tweezers, in the pre-heated 40° C. deionized water. Thewet piece is placed (rough side of skin up) piece on a clean plasticsurface, with 2-3 layers of paper towels underneath (transparency film,or acetate, as commonly is used with overhead projectors was typicallyused as the plastic surface). A new clean plastic surface/acetate isused for subsequent skin sample(s).

Test bar #1 is rotated in a gloved hand (using only disposable polygloves from VWR International) 10 times under the 35° C.±2° C. tapwater. Once finished rotating, Test bar #1 is allowed to stand to drainoff any residual water into the sink.

Working on the plastic surface, the wetted soap bar is taken and appliedto the skin sample for 15 seconds (using a timer) with minimal force,being careful not to rip the skin in the process. Care is taken to tryand rotate bar quickly to use all sides of soap during this process.

The bar is placed aside, and the treated skin surface is lathered(massaged) with an index finger, using minimal (not excessive) force,for 45 seconds, using a timer. Using tweezers, the treated skin isquickly taken to a deionized RT water machine and rinsed under therunning nozzle stream for 15 seconds, using a timer. Using tweezers, therinsed vitro skin is placed on paper towels until completely dry(usually 3-4 hours).

The steps above are repeated with subsequent soap bars. When completelydry, the skin(s) are ready for HPLC analysis, and the ExtractionProcedure.

The pieces of VITRO-SKIN® are carefully cut into approximately 9-16small pieces using tweezers/forceps to hold the pieces during cutting.The cuttings are collected on filter paper, and then poured into labeledscintillation vials. These steps are repeated for all replicates/testsamples. 5 ml of ethanol is added to each sample, and the vials are wellvortexed. The sample lids are closed, and the samples are allowed to sitfor 24 to 48 hours to extract the PE from the VITRO-SKIN® (shorterexposure times can lead to high variability in the results). The timesof the extractions are recorded. The ethanol is removed from the vialsusing disposable glass Pasteur pipettes, and as much of the ethanolextraction as possible is transferred into a labeled Kimble Tube. Theethanol is evaporated from the Kimble tubes with an evaporator (such asGENEVAC). Alternatively, the ethanol can be evaporated over time withopen caps. The samples are capped and stored in the refrigerator untilreconstitution with controlled volumes of solvent and subsequent HPLCanalysis. The results are shown in Table 5 (below).

TABLE 5 0.3% PO + 0.75% Control 0.3% PO + 0.75% PE + 0.75% (0.3% PO) PEPetrolatum ppm of PO Deposited Appx. 7.0 Appx. 7.2 Appx. 9.0

Example 6

Experiments are conducted to determine the antibacterial efficacy of0.75% phenoxyethanol delivered from a bar soap, with and without use ofPE as solvent during processing, using the procedure of Example 2(above). The results of the three (3) hour Ex-vivo Porcine Skin in vitroCup-Scrub studies vs E. coli are shown in Table 6 (below).

TABLE 6 0.3% PO dissolved in 0.75% PE + 0.75% 0.75% PE 0.3% PO 0.75 PE +0.3% PO Petrolatum Mean Log (CFU/7.1 cm²) 1.22 0.44 0.46 2.23 Reductionvs Placebo (E. coli)

The results described in Table 6 (above) demonstrate that that 0.75%phenoxyethanol and 0.3% piroctone olamine delivered individually frombar soap provide a 1.22 and 0.44 log reduction vs. non-antibacterialplacebo bar soap, respectively. The data indicates that the addition ofpetrolatum (0.75%) to the combination of piroctone olamine andphenoxyethanol provides a significantly greater log reduction (2.23)then either phenoxyethanol, piroctone of amine or the combination ofboth.

The data above show the feasibility of adding piroctone olamine as aphenoxyethanol solution up to at least 30% w/w during bar soapmanufacturing, if heated, for example to 80° C. Furthermore, somepiroctone olamine can optionally be supplemented as a solution in afurther solvent, such as a fragrance or a fragrance dissolved in asolvent, preferably up to 7.5% at room temperature.

The in vitro skin deposition study demonstrates significantly enhanceddeposition versus control, and the micro testing suggests solubilizingpiroctone olamine in phenoxyethanol provides an additional benefit forantibacterial activity.

Example 7

Experiments are conducted to determine the antibacterial efficacy of0.75% phenoxyethanol delivered from a bar soap, with and without use ofpropylene glycol as a solvent during processing, using the procedure ofExample 2 (above).

A PO/PG 15% pre-mix solution is prepared by mixing 15 g of piroctoneolamine with 85 g of propylene glycol (PG) and heating to 60° C. for 10minutes, at which time a colorless solution is formed. The premix isadded to an amalgamator, and mixed with a cleanser base to obtain abatch of bar soap, with final levels of 0.75% PE and 0.3% PO. A similarbatch is prepared except that the PO is added as a solid powder, and notdissolved in PG. Incorporation of the PO into the formula issignificantly improved by use of the pre-mixture, as compared toaddition of PO as a solid.

A three (3) hour Ex-vivo Porcine Skin in vitro Cup-Scrub study vs. E.coli is pre-formed on the bar soaps as described above in Example 3. Theresults are shown in Table 7 (below)

TABLE 7 0.75% PE + 0.3% PO 0.75% PE + 0.3% PO (added as powder) (addeddissolved in PG) Mean Log 0.46 1.47 (CFU/7.1 cm²) Reduction vs Placebo(E. coli)

The results show that the addition of PO as a pre-mixture in PG providesa significant increase in the Mean Log Reduction vs. Placebo, indicatingan increased antibacterial efficacy compared to adding PO as a solid(powder).

Example 8

Experiments are conducted to determine the foaming properties of: (1) abar soap containing 0.75% PE; (2) the same formula additionallycontaining 0.3% PO, wherein the PO is added as a powder; and (3) thesame formula additionally containing 0.3% PO, wherein the PO is added inPG solvent as described in Example 6 (above).

The foaming properties of the bar soaps are determined in a proprietarysystem that measured several foaming parameters including amount offoam, foam density, foam stability and foam fluidity. The results ofthese evaluations demonstrate that the foaming properties of a bar soapcontaining 0.75% PE (1) and the formula containing 0.3% PO added in PGsolvent (3) were at parity, while the formula containing 0.3% PO addedas a powder (2) displayed inferior foaming properties.

These results confirm that the use of PG as a solvent for PO in bar soapformulations significantly improves incorporation of PO into the finalformula, and also improves the manufacturing process. It alsosignificantly increased the antibacterial efficacy of the formulation,which is beneficial in terms of potency and the potential for reducingthe PO level, and therefore reducing the cost of PO in the formulation.It also helps mitigate the performance impairment (i.e., reducedfoaming) that might be expected with the use of PO.

What is claimed is:
 1. A personal care composition, comprising acleanser base wherein, the cleanser base comprises at least one cleanserchosen from a soap and a surfactant; and an effective amount of anantibacterial system consisting of: phenoxyethanol, piroctone olamine,and petrolatum; wherein the phenoxyethanol is present in an amount offrom 0.01% to 2% by weight of the personal care composition; wherein thepiroctone olamine is present in an amount of from 0.01% to 1.5% byweight of the personal care composition; and wherein the petrolatum ispresent in an amount of from 0.1% to 0.9% by weight of the personal carecomposition.
 2. The personal care composition of claim 1, wherein thecomposition further comprises propylene glycol.
 3. The personal carecomposition of claim 2, wherein the composition is a cleansing bar. 4.The personal care composition of claim 1, wherein the phenoxyethanol ispresent in an amount of from 0.1% to 1.25% by weight; or from 0.5% to 1%by weight; or from 0.65% to 0.85% by weight; or about 0.75% by weight ofthe personal care composition.
 5. The personal care composition of claim1, wherein the piroctone olamine is present in an amount of from 0.01%to 1% by weight; of from 0.01% to 0.5% by weight; of from 0.05% to 0.3%by weight; of from 0.05% to 0.15% by weight; of from 0.2% to 0.4%; orabout 0.1% by weight; or about 0.3% by weight of the personal carecomposition.
 6. The personal care composition of claim 1, wherein thepetrolatum is present in an amount of from 0.1% to 0.5% by weight; orfrom 0.3% to 0.9% by weight; or from 0.3% to 0.7% by weight; or from 0.3to 0.5% by weight of the personal care composition.
 7. The personal carecomposition of claim 1, wherein the phenoxyethanol is present in anamount of from 0.65% to 0.85% by weight of the personal carecomposition.
 8. The personal care composition of claim 1, wherein thepiroctone olamine is present in an amount of from 0.2% to 0.4% by weightof the personal care composition.
 9. The personal care composition ofclaim 1, wherein the phenoxyethanol is present in an amount of from0.65% to 0.85% by weight of the personal care composition; the piroctoneolamine is present in an amount of from 0.2% to 0.4% by weight of thepersonal care composition; and the petrolatum is present in an amount offrom 0.3% to 0.9% by weight of the personal care composition.
 10. Thepersonal care composition of claim 1, wherein the personal carecomposition comprises two or more surfactants or soaps.
 11. The personalcare composition of claim 1, wherein the at least one cleanser comprisessoap chips, anionic surfactants, nonionic surfactants, cationicsurfactants; amphoteric surfactants, and zwitterionic surfactants.
 12. Amethod of removing bacteria from skin comprising washing said skin witha personal care composition according to claim
 2. 13. A method ofinhibiting bacterial growth on skin comprising washing said skin with apersonal care composition according to claim 2.